Coordination Polymers Based on Cobridging of Rigid and Flexible Spacer Ligands:  Syntheses, Crystal Structures, and Magnetic Properties of [Mn(bpy)(H2O)(C4H4O4)]·0.5bpy, Mn(bpy)(C5H6O4), and Mn(bpy)(C6H8O4)

• Published in: Inorganic chemistry 2004-04, Vol.43 (8), p.2590-2596
• Main Authors: Zheng, Y.-Q, Lin, J.-L, Kong, Z.-P
• Format: Article
• Language: English
• ISSN: 0020-1669; 1520-510X
• DOI: 10.1021/ic0301268

Reactions of 4,4‘-bipyridine (bpy) with Mn(C4H4O4)·4H2O and Mn(C5H6O4)·4H2O in methanolic aqueous solutions yielded [Mn(bpy)(H2O)(C4H4O4)]·0.5bpy (1) and Mn(bpy)(C5H6O4) (2), respectively, and reactions of freshly prepared Mn(OH)2 - 2 x (CO3) x ·yH2O, adipic acid and 4,4‘-bipyridine in a methanolic aqueous solution afforded Mn(bpy)(C6H8O4) (3). The six-coordinate Mn atoms in 1 are interlinked by flexible succinato ligands to form layers, which are sustained by rigid bpy ligands into an 3D open framework with the free bpy molecules in tunnels. The ribbonlike chains in 2 result from Mn atoms bridged by glutarato ligands and are connected by bpy ligands into open layers. In 3, the Mn atoms are bridged by both bpy and adipato ligands to form 3D nanoporous frameworks and 2-fold interpenetration of the resulting 3D frameworks completes the crystal structure. In comparison with 1 and 2, compound 3 displays significant antiferromagnetic behavior at low temperature. The antiferromagnetic exchange becomes stronger from 1 through 2 to 3, and the antiferromagnetic ordering of Mn2+ centers is related to the syn−syn bridging mode of the terminal carboxylate groups of α,ω-dicarboxylate anions. Crystal data:  C19H18MnN3O5 (1), monoclinic P21/c, a = 11.686(2) Å, b = 17.847(2) Å, c = 8.852(1) Å, β = 99.67(1)°, V = 1819.9(4) Å3, Z = 4, D c = 1.545 g·cm-3; C15H14MnN2O4 (2), triclinic P1̄, a = 8.145(2) Å, b = 9.574(2) Å, c = 10.180(1) Å, α = 108.01(3)°, β = 93.55(3)°, γ = 105.30(1)°, V = 719.2(2) Å3, Z = 2, D c = 1.576 g·cm-3; C15H14MnN2O4 (3), triclinic P1̄, a = 8.544(1) Å, b = 8.881(1) Å, c = 10.949(2) Å, α = 108.81(1)°, β = 95.40(1)°, γ = 101.94(1)°, V = 757.7(2) Å3, Z = 2, D c = 1.557 g·cm-3.